碱性-乙醇法脱除茶叶中咖啡因的工艺优化

Process Optimization of Caffeine Removal from Tea by Alkaline-Ethanol Method

试验以茶叶为原料,采取了碱性-乙醇法脱除咖啡因,为生产低咖啡因产品或者无咖啡因产品提供技术和理论的借鉴。以EGCG的保留率、咖啡因的残留率、EGCG与咖啡因的相对分离度为指标,以提取次数、NaOH的用量、料液比、水和乙醇的比例、搅拌提取时间和提取温度为因素,优化碱性乙醇脱除咖啡因的最佳条件。最佳条件为提取次数6次、Na OH的用量0.1%、料液比1∶10 (g/mL)、水和乙醇的比例3∶97 (V/V)、搅拌提取时间2.5 h和提取温度25℃。在此条件下咖啡因的脱除率高达97%,并且咖啡因和EGCG能够有效地分离, EGCG的保留率为95%,咖啡因的残留率为3%,相对分离度为30.16。

In this study,tea was used as raw material to remove caffeine by alkaline-ethanol method,which provided technical and theoretical reference for the production of decaffeinated products or decaffeinated products.With the retention rate of EGCG,the residual rate of caffeine,the relative separation degree of EGCG and caffeine as indexes,the extraction times,the amount of NaOH,the ratio of solid to liquid,the ratio of water to ethanol,the extraction time of stirring and the extraction temperature were used as the factors to optimize the conditions for the removal of caffeine by alkaline ethanol.The optimum conditions were extraction times of 6,dosage of NaOH 0.1%,solid-liquid ratio 1:10(g/mL),ratio of water to ethanol 3:97(V/V),stirring extraction time 2.5 h and extraction temperature 25 C.Under these conditions,the caffeine removal rate was as high as 97%,and caffeine and EGCG could be effectively separated.The retention rate of EGCG was 95%,the residual rate of caffeine was 3%,and the relative separation degree was 30.16.